Opinions on this driver.

[pjeva]

Would harmonics and spurii show up as extra power on a power meter?

Yes. Coupler in power meter will pick up everything. That is why you should always measure after LPF.



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[Spokes]

did you get round to testing the driver board or has anyone else ended up buying one?

[MiXiN]

did you get round to testing the driver board or has anyone else ended up buying one?

I've seen it connected to a power meter and what my friend says holds true in that it does 900mW to 1.1W throughout the band. Some of the power might be harmonics as said above though, but as my pal hasn't any decent analysis gear we'll never know.

I've not heard any audio from it, but I'll definitely be seeing him this Friday so will get him to feed some modulation in and report back.

Just noticed earlier yesterday that the guy who sells these is throwing in a RDS unit for the first 10 purchases, but I have no idea if his RDS units are any good?

[Shedbuilt]

That logo was drawn by me, it was on all my stuff

Then rf-head copied it off me about 2 years ago and started printed it on his stuff which at the time I was unhappy about, we are cool now I must add haha.

Now whoever this guy is building these exciters claiming 1 watt from a 3866 with a similar logo.... Unbelievable

...and that logo with the guy sticking his middle finger up was first used by Broadcast Warehouse many many years ago! Unbelievable.

...oh wait, so was that whole driver design (RF bit, anyway).

Haha, rumbled!

I think the RF part goes back further than BW, to be honest......
Edit: Sorry fellow necks; inadvertently bumped an old post

[Albert H]

...and that logo with the guy sticking his middle finger up was first used by Broadcast Warehouse many many years ago! Unbelievable.

...oh wait, so was that whole driver design (RF bit, anyway).

Haha, rumbled!

I think the RF part goes back further than BW, to be honest......
Edit: Sorry fellow necks; inadvertently bumped an old post

The RF design of this one dates back to the late 70s, probably from either Bill K or possibly from Carl D (both from RFL). The transistors used in those days were BSX20 and 2N4427. The original circuit had a TTL-based PLL and was a doubler - doubler circuit. Later, the oscillator was changed to run at half frequency, and the PLL was simplified (my four-chip 74HC CMOS circuit). Back in the early 80s, there were several runs of PCBs for this kind of circuit - they were the first to have an on-board PLL. The transformer driving the '4427 was wound on a couple of ferrite beads back then - the Amidon "polo-mints" were a bit exotic for us back then! It was the first exciter circuit to eliminate trimmer capacitors as soon as the Toko S18s became available from Ambit.

Roger pinched the basic circuit from one of the boards he saw at my place. He simplified the oscillator (mine used separate tuning and modulation varicaps), and degraded the noise performance a lot.

I was thinking of 3-D printing some "S18" coils and doing a run of PCBs. With a little work, they could be 1 Watt, 5 Watts and 12 Watts, with really cheap components and no PICs to programme!